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          15个 MySQL 基础面试题，DBA 们准备好了吗？
         </a>
        </h1>
        <address class="msccaddress ">
         <em>
          1,777 次阅读 -
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          基础架构
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       </p>
       <h3>
        问题1：你如何确定 MySQL 是否处于运行状态？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ： Debian 上运行命令
         <strong>
          service mysql status
         </strong>
         ，在RedHat 上运行命令
         <strong>
          service mysqld status
         </strong>
         。然后看看输出即可。
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          root@localhost:/home/avi# service mysql status

/usr/bin/mysqladmin  Ver 8.42 Distrib 5.1.72, for debian-linux-gnu on i486
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Server version 5.1.72-2
Protocol version 10
Connection Localhost via UNIX socket
UNIX socket /var/run/mysqld/mysqld.sock
Uptime: 1 hour 22 min 49 sec

Threads: 1  Questions: 112138  Slow queries: 1  Opens: 1485  Flush tables: 1  Open tables: 64  Queries per second avg: 22.567.
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               15
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               16
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             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113f8c574179154-1">
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                root
               </span>
               <span class="crayon-sy">
                @
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                localhost
               </span>
               <span class="crayon-o">
                :
               </span>
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                /
               </span>
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                home
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                /
               </span>
               <span class="crayon-v">
                avi
               </span>
               <span class="crayon-p">
                # service mysql status
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-2">
              </div>
              <div class="crayon-line" id="crayon-5768660113f8c574179154-3">
               <span class="crayon-o">
                /
               </span>
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                usr
               </span>
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                /
               </span>
               <span class="crayon-v">
                bin
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-e">
                mysqladmin
               </span>
               <span class="crayon-i">
                Ver
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                8.42
               </span>
               <span class="crayon-h">
               </span>
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                Distrib
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                5.1.72
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                for
               </span>
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               </span>
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                debian
               </span>
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                -
               </span>
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                linux
               </span>
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                -
               </span>
               <span class="crayon-e">
                gnu
               </span>
               <span class="crayon-e">
                on
               </span>
               <span class="crayon-e">
                i486
               </span>
              </div>
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                (
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               </span>
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                )
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                2000
               </span>
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               </span>
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                2013
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                Oracle
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              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-8">
               <span class="crayon-v">
                owners
               </span>
               <span class="crayon-sy">
                .
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113f8c574179154-9">
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-10">
               <span class="crayon-e">
                Server
               </span>
               <span class="crayon-i">
                version
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                5.1.72
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                2
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113f8c574179154-11">
               <span class="crayon-e">
                Protocol
               </span>
               <span class="crayon-i">
                version
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                10
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-12">
               <span class="crayon-e">
                Connection
               </span>
               <span class="crayon-e">
                Localhost
               </span>
               <span class="crayon-e">
                via
               </span>
               <span class="crayon-e">
                UNIX
               </span>
               <span class="crayon-e">
                socket
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113f8c574179154-13">
               <span class="crayon-e">
                UNIX
               </span>
               <span class="crayon-v">
                socket
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-t">
                var
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                run
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                mysqld
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                mysqld
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-e">
                sock
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-14">
               <span class="crayon-v">
                Uptime
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-i">
                hour
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                22
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-i">
                min
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                49
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                sec
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113f8c574179154-15">
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f8c574179154-16">
               <span class="crayon-v">
                Threads
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Questions
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                112138
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Slow
               </span>
               <span class="crayon-v">
                queries
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Opens
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                1485
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Flush
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Open
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                64
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Queries
               </span>
               <span class="crayon-e">
                per
               </span>
               <span class="crayon-e">
                second
               </span>
               <span class="crayon-v">
                avg
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                22.567.
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0197 seconds] -->
       <p>
       </p>
       <h3>
        问题2：如何开启或停止 MySQL 服务？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          service mysqld start
         </strong>
         开启服务；运行命令
         <strong>
          service mysqld stop
         </strong>
         停止服务。
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113f9d639074794" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
        <div class="crayon-toolbar" data-settings=" mouseover overlay hide delay" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;">
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           </div>
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        </div>
        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          root@localhost:/home/avi# service mysql stop

Stopping MySQL database server: mysqld.

root@localhost:/home/avi# service mysql start

Starting MySQL database server: mysqld.

Checking for corrupt, not cleanly closed and upgrade needing tables..
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113f9d639074794-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113f9d639074794-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113f9d639074794-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113f9d639074794-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113f9d639074794-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113f9d639074794-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113f9d639074794-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113f9d639074794-8">
               8
              </div>
              <div class="crayon-num" data-line="crayon-5768660113f9d639074794-9">
               9
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113f9d639074794-1">
               <span class="crayon-v">
                root
               </span>
               <span class="crayon-sy">
                @
               </span>
               <span class="crayon-v">
                localhost
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                home
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                avi
               </span>
               <span class="crayon-p">
                # service mysql stop
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f9d639074794-2">
              </div>
              <div class="crayon-line" id="crayon-5768660113f9d639074794-3">
               <span class="crayon-e">
                Stopping
               </span>
               <span class="crayon-e">
                MySQL
               </span>
               <span class="crayon-e">
                database
               </span>
               <span class="crayon-v">
                server
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                mysqld
               </span>
               <span class="crayon-sy">
                .
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f9d639074794-4">
              </div>
              <div class="crayon-line" id="crayon-5768660113f9d639074794-5">
               <span class="crayon-v">
                root
               </span>
               <span class="crayon-sy">
                @
               </span>
               <span class="crayon-v">
                localhost
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                home
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                avi
               </span>
               <span class="crayon-p">
                # service mysql start
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f9d639074794-6">
              </div>
              <div class="crayon-line" id="crayon-5768660113f9d639074794-7">
               <span class="crayon-e">
                Starting
               </span>
               <span class="crayon-e">
                MySQL
               </span>
               <span class="crayon-e">
                database
               </span>
               <span class="crayon-v">
                server
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                mysqld
               </span>
               <span class="crayon-sy">
                .
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113f9d639074794-8">
              </div>
              <div class="crayon-line" id="crayon-5768660113f9d639074794-9">
               <span class="crayon-e">
                Checking
               </span>
               <span class="crayon-st">
                for
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                corrupt
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                not
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                cleanly
               </span>
               <span class="crayon-e">
                closed
               </span>
               <span class="crayon-st">
                and
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                upgrade
               </span>
               <span class="crayon-e">
                needing
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-sy">
                .
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0082 seconds] -->
       <p>
       </p>
       <h3>
        问题3：如何通过 Shell 登入 MySQL？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          mysql -u root -p
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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        <div class="crayon-toolbar" data-settings=" mouseover overlay hide delay" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;">
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           </div>
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           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-expand-button" title="点击展开代码">
           <div class="crayon-button-icon">
           </div>
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           <div class="crayon-button-icon">
           </div>
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           <div class="crayon-button-icon">
           </div>
          </div>
         </div>
        </div>
        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          root@localhost:/home/avi# mysql -u root -p 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g. 
Your MySQL connection id is 207 
Server version: 5.1.72-2 (Debian) 

Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. 

Oracle is a registered trademark of Oracle Corporation and/or its 
affiliates. Other names may be trademarks of their respective 
owners. 

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. 

mysql&amp;gt;
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-8">
               8
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-9">
               9
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-10">
               10
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-11">
               11
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-12">
               12
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-13">
               13
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fa4804682228-14">
               14
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fa4804682228-15">
               15
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fa4804682228-1">
               <span class="crayon-v">
                root
               </span>
               <span class="crayon-sy">
                @
               </span>
               <span class="crayon-v">
                localhost
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                home
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                avi
               </span>
               <span class="crayon-p">
                # mysql -u root -p
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fa4804682228-2">
               <span class="crayon-e">
                Enter
               </span>
               <span class="crayon-v">
                password
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fa4804682228-3">
               <span class="crayon-e">
                Welcome
               </span>
               <span class="crayon-st">
                to
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                the
               </span>
               <span class="crayon-e">
                MySQL
               </span>
               <span class="crayon-v">
                monitor
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Commands
               </span>
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             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0141 seconds] -->
       <p>
       </p>
       <h3>
        问题4：如何列出所有数据库？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          show databases;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113fab398716971" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
        <div class="crayon-toolbar" data-settings=" mouseover overlay hide delay" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;">
         <span class="crayon-title">
         </span>
         <div class="crayon-tools" style="font-size: 12px !important;height: 18px !important; line-height: 18px !important;">
          <div class="crayon-button crayon-nums-button" title="切换是否显示行编号">
           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-plain-button" title="纯文本显示代码">
           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-wrap-button" title="切换自动换行">
           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-expand-button" title="点击展开代码">
           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-copy-button" title="复制代码">
           <div class="crayon-button-icon">
           </div>
          </div>
          <div class="crayon-button crayon-popup-button" title="在新窗口中显示代码">
           <div class="crayon-button-icon">
           </div>
          </div>
         </div>
        </div>
        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; show databases; 
+--------------------+ 
| Database           | 
+--------------------+ 
| information_schema | 
| a1                 | 
| cloud              | 
| mysql              | 
| phpmyadmin         | 
| playsms            | 
| sisso              | 
| test               | 
| ukolovnik          | 
| wordpress          | 
+--------------------+ 
10 rows in set (0.14 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-8">
               8
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-9">
               9
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-10">
               10
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-11">
               11
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-12">
               12
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-13">
               13
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-14">
               14
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fab398716971-15">
               15
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fab398716971-16">
               16
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fab398716971-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
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               <span class="crayon-h">
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               <span class="crayon-e">
                show
               </span>
               <span class="crayon-v">
                databases
               </span>
               <span class="crayon-sy">
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               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-2">
               <span class="crayon-o">
                +
               </span>
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               <span class="crayon-o">
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               <span class="crayon-o">
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                --
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               <span class="crayon-o">
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               <span class="crayon-o">
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               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-3">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Database
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-4">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-5">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                information_schema
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-6">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                a1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-7">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                cloud
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-8">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-9">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                phpmyadmin
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-10">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                playsms
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-11">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sisso
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-12">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                test
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-13">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                ukolovnik
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-14">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                wordpress
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               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fab398716971-15">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fab398716971-16">
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                set
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.14
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0078 seconds] -->
       <p>
       </p>
       <h3>
        问题5： 如何切换到某个数据库并在上面工作？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          use database_name;
         </strong>
         进入名为 database_name 的数据库。
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113fb1703605618" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
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        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; use cloud; 
Reading table information for completion of table and column names 
You can turn off this feature to get a quicker startup with -A 

Database changed 
mysql&amp;gt;
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
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            <td class="crayon-nums " data-settings="show">
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              <div class="crayon-num" data-line="crayon-5768660113fb1703605618-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb1703605618-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fb1703605618-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb1703605618-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fb1703605618-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb1703605618-6">
               6
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fb1703605618-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                use
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                cloud
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb1703605618-2">
               <span class="crayon-e">
                Reading
               </span>
               <span class="crayon-e">
                table
               </span>
               <span class="crayon-e">
                information
               </span>
               <span class="crayon-st">
                for
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                completion
               </span>
               <span class="crayon-e">
                of
               </span>
               <span class="crayon-e">
                table
               </span>
               <span class="crayon-st">
                and
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                column
               </span>
               <span class="crayon-e">
                names
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb1703605618-3">
               <span class="crayon-e">
                You
               </span>
               <span class="crayon-e">
                can
               </span>
               <span class="crayon-e">
                turn
               </span>
               <span class="crayon-e">
                off
               </span>
               <span class="crayon-r">
                this
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                feature
               </span>
               <span class="crayon-st">
                to
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-i">
                get
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-i">
                a
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                quicker
               </span>
               <span class="crayon-e">
                startup
               </span>
               <span class="crayon-v">
                with
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-i">
                A
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb1703605618-4">
              </div>
              <div class="crayon-line" id="crayon-5768660113fb1703605618-5">
               <span class="crayon-e">
                Database
               </span>
               <span class="crayon-e">
                changed
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb1703605618-6">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0021 seconds] -->
       <p>
       </p>
       <h3>
        问题6：如何列出某个数据库内所有表？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：在当前数据库运行命令
         <strong>
          show tables;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113fb7589007075" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
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           </div>
          </div>
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           </div>
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           </div>
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        </div>
        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
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         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; show tables; 
+----------------------------+ 
| Tables_in_cloud            | 
+----------------------------+ 
| oc_appconfig               | 
| oc_calendar_calendars      | 
| oc_calendar_objects        | 
| oc_calendar_repeat         | 
| oc_calendar_share_calendar | 
| oc_calendar_share_event    | 
| oc_contacts_addressbooks   | 
| oc_contacts_cards          | 
| oc_fscache                 | 
| oc_gallery_sharing         | 
+----------------------------+ 
10 rows in set (0.00 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
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              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb7589007075-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb7589007075-4">
               4
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              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb7589007075-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb7589007075-8">
               8
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-9">
               9
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fb7589007075-10">
               10
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               11
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              <div class="crayon-num" data-line="crayon-5768660113fb7589007075-13">
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               14
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               15
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               16
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             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fb7589007075-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                show
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-2">
               <span class="crayon-o">
                +
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-3">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Tables_in_cloud
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-4">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-5">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_appconfig
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-6">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_calendar_calendars
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-7">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_calendar_objects
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-8">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_calendar_repeat
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-9">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_calendar_share_calendar
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-10">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_calendar_share_event
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-11">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_contacts_addressbooks
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-12">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_contacts_cards
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-13">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_fscache
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-14">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                oc_gallery_sharing
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fb7589007075-15">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fb7589007075-16">
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                set
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.00
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0205 seconds] -->
       <p>
       </p>
       <h3>
        问题7：如何获取表内所有 Field 对象的名称和类型？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          describe table_name;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113fbe720675995" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
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        </div>
        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; describe oc_users; 
+----------+--------------+------+-----+---------+-------+ 
| Field    | Type         | Null | Key | Default | Extra | 
+----------+--------------+------+-----+---------+-------+ 
| uid      | varchar(64)  | NO   | PRI |         |       | 
| password | varchar(255) | NO   |     |         |       | 
+----------+--------------+------+-----+---------+-------+ 
2 rows in set (0.00 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
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              <div class="crayon-num" data-line="crayon-5768660113fbe720675995-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fbe720675995-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fbe720675995-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fbe720675995-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fbe720675995-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fbe720675995-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fbe720675995-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fbe720675995-8">
               8
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fbe720675995-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                describe
               </span>
               <span class="crayon-v">
                oc_users
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fbe720675995-2">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fbe720675995-3">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Field
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Type
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-t">
                Null
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Key
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                Default
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Extra
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fbe720675995-4">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fbe720675995-5">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                uid
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                varchar
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                64
               </span>
               <span class="crayon-sy">
                )
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                PRI
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fbe720675995-6">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                password
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                varchar
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                255
               </span>
               <span class="crayon-sy">
                )
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fbe720675995-7">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fbe720675995-8">
               <span class="crayon-cn">
                2
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                set
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.00
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0224 seconds] -->
       <p>
       </p>
       <h3>
        问题8：如何删除表？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          drop table table_name;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
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         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; drop table lookup; 

Query OK, 0 rows affected (0.00 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113fc4219877154-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fc4219877154-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fc4219877154-3">
               3
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fc4219877154-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                drop
               </span>
               <span class="crayon-e">
                table
               </span>
               <span class="crayon-v">
                lookup
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fc4219877154-2">
              </div>
              <div class="crayon-line" id="crayon-5768660113fc4219877154-3">
               <span class="crayon-e">
                Query
               </span>
               <span class="crayon-v">
                OK
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                0
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-e">
                affected
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.00
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0012 seconds] -->
       <p>
       </p>
       <h3>
        问题9：如何删除数据库？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          drop database database-name;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
        <div class="crayon-plain-wrap">
         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; drop database a1; 

Query OK, 11 rows affected (0.07 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113fca411910560-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fca411910560-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fca411910560-3">
               3
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fca411910560-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                drop
               </span>
               <span class="crayon-e">
                database
               </span>
               <span class="crayon-v">
                a1
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fca411910560-2">
              </div>
              <div class="crayon-line" id="crayon-5768660113fca411910560-3">
               <span class="crayon-e">
                Query
               </span>
               <span class="crayon-v">
                OK
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                11
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-e">
                affected
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.07
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0013 seconds] -->
       <p>
       </p>
       <h3>
        问题10：如何查看表内所有数据？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select * from table_name;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
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         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; select * from engines; 
+------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
| ENGINE     | SUPPORT | COMMENT                                                        | TRANSACTIONS | XA   | SAVEPOINTS | 
+------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
| InnoDB     | YES     | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        | 
| MRG_MYISAM | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         | 
| BLACKHOLE  | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         | 
| CSV        | YES     | CSV storage engine                                             | NO           | NO   | NO         | 
| MEMORY     | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         | 
| FEDERATED  | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       | 
| ARCHIVE    | YES     | Archive storage engine                                         | NO           | NO   | NO         | 
| MyISAM     | DEFAULT | Default engine as of MySQL 3.23 with great performance         | NO           | NO   | NO         | 
+------------+---------+----------------------------------------------------------------+--------------+------+------------+ 
8 rows in set (0.00 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
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            <td class="crayon-nums " data-settings="show">
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              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-8">
               8
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-9">
               9
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-10">
               10
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-11">
               11
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-12">
               12
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fd0386498333-13">
               13
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fd0386498333-14">
               14
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fd0386498333-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e ">
                select *
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                from
               </span>
               <span class="crayon-v">
                engines
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-2">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-3">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                ENGINE
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                SUPPORT
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                COMMENT
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                TRANSACTIONS
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                XA
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                SAVEPOINTS
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-4">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-5">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                InnoDB
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Supports
               </span>
               <span class="crayon-v">
                transactions
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                row
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-e">
                level
               </span>
               <span class="crayon-v">
                locking
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                and
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                foreign
               </span>
               <span class="crayon-v">
                keys
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-6">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MRG_MYISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Collection
               </span>
               <span class="crayon-e">
                of
               </span>
               <span class="crayon-e">
                identical
               </span>
               <span class="crayon-e">
                MyISAM
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-7">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                BLACKHOLE
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-v">
                dev
               </span>
               <span class="crayon-o">
                /
               </span>
               <span class="crayon-t">
                null
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                storage
               </span>
               <span class="crayon-e">
                engine
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-e">
                anything
               </span>
               <span class="crayon-e">
                you
               </span>
               <span class="crayon-e">
                write
               </span>
               <span class="crayon-st">
                to
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                it
               </span>
               <span class="crayon-v">
                disappears
               </span>
               <span class="crayon-sy">
                )
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-8">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                CSV
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                CSV
               </span>
               <span class="crayon-e">
                storage
               </span>
               <span class="crayon-v">
                engine
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-9">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MEMORY
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Hash
               </span>
               <span class="crayon-v">
                based
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                stored
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                memory
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                useful
               </span>
               <span class="crayon-st">
                for
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                temporary
               </span>
               <span class="crayon-v">
                tables
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-10">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                FEDERATED
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Federated
               </span>
               <span class="crayon-e">
                MySQL
               </span>
               <span class="crayon-e">
                storage
               </span>
               <span class="crayon-v">
                engine
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-t">
                NULL
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-t">
                NULL
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-t">
                NULL
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-11">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                ARCHIVE
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                YES
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                Archive
               </span>
               <span class="crayon-e">
                storage
               </span>
               <span class="crayon-v">
                engine
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-12">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                DEFAULT
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                Default
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                engine
               </span>
               <span class="crayon-st">
                as
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                of
               </span>
               <span class="crayon-i">
                MySQL
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                3.23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                with
               </span>
               <span class="crayon-e">
                great
               </span>
               <span class="crayon-v">
                performance
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                NO
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd0386498333-13">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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                +
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               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fd0386498333-14">
               <span class="crayon-cn">
                8
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-st">
                in
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               </span>
               <span class="crayon-e">
                set
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                (
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               <span class="crayon-cn">
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        </div>
       </div>
       <!-- [Format Time: 0.0393 seconds] -->
       <p>
       </p>
       <h3>
        问题11：如何从表（比如 oc_users ）中获取一个 field 对象（比如 uid）的所有数据？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select uid from oc_users;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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          mysql&amp;gt; select uid from oc_users; 
+-----+ 
| uid | 
+-----+ 
| avi | 
+-----+ 
1 row in set (0.03 sec)
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
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               4
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               5
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               6
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               7
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             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fd7679519284-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                select
               </span>
               <span class="crayon-e">
                uid
               </span>
               <span class="crayon-e">
                from
               </span>
               <span class="crayon-v">
                oc_users
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
              </div>
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               <span class="crayon-o">
                +
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                --
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                --
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              <div class="crayon-line" id="crayon-5768660113fd7679519284-3">
               <span class="crayon-o">
                |
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               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                uid
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
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               <span class="crayon-o">
                +
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                --
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                +
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              </div>
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               <span class="crayon-o">
                |
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               <span class="crayon-h">
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                avi
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
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               <span class="crayon-h">
               </span>
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                +
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                --
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                -
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                +
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               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fd7679519284-7">
               <span class="crayon-cn">
                1
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                row
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                set
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.03
               </span>
               <span class="crayon-h">
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               <span class="crayon-v">
                sec
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               <span class="crayon-sy">
                )
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        </div>
       </div>
       <!-- [Format Time: 0.0021 seconds] -->
       <p>
       </p>
       <h3>
        问题12：假设你有一个名为 ‘xyz’ 的表，它存在多个字段，如 ‘create
        <em>
         time’ 和 ‘engine’。名为 engine 的字段由 ‘Memoty’ 和 ‘MyIsam’ 两种数值组成。如何只列出 ‘create
        </em>
        time’ 和 ‘engine’ 这两列并且 engine 的值为 ‘MyIsam’？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select create_time, engine from xyz where engine = ”MyIsam”;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
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          mysql&amp;gt; select create_time, engine from xyz where engine="MyIsam";

+---------------------+--------+ 
| create_time         | engine | 
+---------------------+--------+ 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-12-15 13:43:27 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
| 2013-10-23 14:56:38 | MyISAM | 
+---------------------+--------+ 
132 rows in set (0.29 sec)
         </textarea>
        </div>
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               13
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               14
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               15
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               16
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               17
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               18
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               19
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               20
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               21
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               22
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fde503860824-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                select
               </span>
               <span class="crayon-v">
                create_time
               </span>
               <span class="crayon-sy">
                ,
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                engine
               </span>
               <span class="crayon-e">
                from
               </span>
               <span class="crayon-e">
                xyz
               </span>
               <span class="crayon-e">
                where
               </span>
               <span class="crayon-v">
                engine
               </span>
               <span class="crayon-o">
                =
               </span>
               <span class="crayon-s">
                "MyIsam"
               </span>
               <span class="crayon-sy">
                ;
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-2">
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-3">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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                --
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                --
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                --
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                --
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                --
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                --
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                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-4">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                create_time
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                engine
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-5">
               <span class="crayon-o">
                +
               </span>
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                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
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                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-6">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-7">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-8">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-9">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-10">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-11">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-12">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-13">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                12
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                15
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                43
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                27
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-14">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-15">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-16">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-17">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-18">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-19">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-20">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                2013
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                10
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-cn">
                23
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                14
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                56
               </span>
               <span class="crayon-o">
                :
               </span>
               <span class="crayon-cn">
                38
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                MyISAM
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fde503860824-21">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fde503860824-22">
               <span class="crayon-cn">
                132
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                rows
               </span>
               <span class="crayon-st">
                in
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                set
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.29
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                sec
               </span>
               <span class="crayon-sy">
                )
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0264 seconds] -->
       <p>
       </p>
       <h3>
        问题13：如何列出表 ‘xrt’ 内 name 域值为 ‘tecmint’，web_address 域值为 ‘tecmint.com’ 的所有数据？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select * from xrt where name = “tecmint” and web_address = “tecmint.com”;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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          mysql&amp;gt; select  * from xrt where name = "tecmint" and web_address = “tecmint.com”;
+---------------+---------------------+---------------+ 
| Id                  | name                   | web_address | 
+---------------+---------------------+----------------+ 
| 13                 |  tecmint               | tecmint.com  |
+---------------+---------------------+----------------+ 
| 41                 |  tecmint               | tecmint.com  |
+---------------+---------------------+----------------+
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113fe5581435646-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fe5581435646-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fe5581435646-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fe5581435646-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fe5581435646-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fe5581435646-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113fe5581435646-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113fe5581435646-8">
               8
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
              <div class="crayon-line" id="crayon-5768660113fe5581435646-1">
               <span class="crayon-v">
                mysql
               </span>
               <span class="crayon-o">
                &amp;
               </span>
               <span class="crayon-v">
                gt
               </span>
               <span class="crayon-sy">
                ;
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e ">
                select  *
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-e">
                from
               </span>
               <span class="crayon-e">
                xrt
               </span>
               <span class="crayon-e">
                where
               </span>
               <span class="crayon-v">
                name
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                =
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-s">
                "tecmint"
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-st">
                and
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                web_address
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                =
               </span>
               <span class="crayon-h">
               </span>
               “
               <span class="crayon-v">
                tecmint
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-i">
                com
               </span>
               ”
               <span class="crayon-sy">
                ;
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fe5581435646-2">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fe5581435646-3">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                Id
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                name
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                web_address
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fe5581435646-4">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fe5581435646-5">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                13
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                tecmint
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                tecmint
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-v">
                com
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fe5581435646-6">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line" id="crayon-5768660113fe5581435646-7">
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-cn">
                41
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                tecmint
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-v">
                tecmint
               </span>
               <span class="crayon-sy">
                .
               </span>
               <span class="crayon-v">
                com
               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-o">
                |
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113fe5581435646-8">
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                -
               </span>
               <span class="crayon-o">
                +
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                --
               </span>
               <span class="crayon-o">
                +
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0127 seconds] -->
       <p>
       </p>
       <h3>
        问题14：如何列出表 ‘xrt’ 内 name 域值不为 ‘tecmint’，web_address 域值为 ‘tecmint.com’ 的所有数据？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select * from xrt where name != “tecmint” and web_address = “tecmint.com”;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
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        <div class="crayon-info" style="min-height: 16.8px !important; line-height: 16.8px !important;">
        </div>
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         <textarea class="crayon-plain print-no" data-settings="dblclick" readonly="" style="-moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4; font-size: 12px !important; line-height: 15px !important;" wrap="soft">
          mysql&amp;gt; select * from xrt where name != ”tecmint” and web_address = ”tecmint.com”;

+---------------+---------------------+---------------+ 
| Id            | name                | web_address   | 
+---------------+---------------------+----------------+ 
| 1173          |  tecmint            | tecmint.com   |
+---------------+---------------------+----------------+
         </textarea>
        </div>
        <div class="crayon-main" style="">
         <table class="crayon-table">
          <tbody>
           <tr class="crayon-row">
            <td class="crayon-nums " data-settings="show">
             <div class="crayon-nums-content" style="font-size: 12px !important; line-height: 15px !important;">
              <div class="crayon-num" data-line="crayon-5768660113feb625514710-1">
               1
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113feb625514710-2">
               2
              </div>
              <div class="crayon-num" data-line="crayon-5768660113feb625514710-3">
               3
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113feb625514710-4">
               4
              </div>
              <div class="crayon-num" data-line="crayon-5768660113feb625514710-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113feb625514710-6">
               6
              </div>
              <div class="crayon-num" data-line="crayon-5768660113feb625514710-7">
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                +
               </span>
              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0115 seconds] -->
       <p>
       </p>
       <h3>
        问题15：如何知道表内行数？
       </h3>
       <blockquote>
        <p>
         <strong>
          答案
         </strong>
         ：运行命令
         <strong>
          select count(*) from table_name;
         </strong>
        </p>
       </blockquote>
       <h2>
       </h2>
       <p>
       </p>
       <!-- Crayon Syntax Highlighter v_2.7.2_beta -->
       <div class="crayon-syntax crayon-theme-classic crayon-font-monaco crayon-os-pc print-yes notranslate" data-settings=" minimize scroll-mouseover" id="crayon-5768660113ff1937616296" style=" margin-top: 12px; margin-bottom: 12px; font-size: 12px !important; line-height: 15px !important;">
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          mysql&amp;gt; select count(*) from Tables; 

+----------+ 
| count(*) | 
+----------+ 
|      282 | 
+----------+ 
1 row in set (0.01 sec)
         </textarea>
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        <div class="crayon-main" style="">
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               3
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              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113ff1937616296-4">
               4
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              <div class="crayon-num" data-line="crayon-5768660113ff1937616296-5">
               5
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113ff1937616296-6">
               6
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              <div class="crayon-num" data-line="crayon-5768660113ff1937616296-7">
               7
              </div>
              <div class="crayon-num crayon-striped-num" data-line="crayon-5768660113ff1937616296-8">
               8
              </div>
             </div>
            </td>
            <td class="crayon-code">
             <div class="crayon-pre" style="font-size: 12px !important; line-height: 15px !important; -moz-tab-size:4; -o-tab-size:4; -webkit-tab-size:4; tab-size:4;">
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                gt
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                Tables
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               </span>
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               <span class="crayon-h">
               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113ff1937616296-4">
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               <span class="crayon-e">
                count
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               <span class="crayon-h">
               </span>
              </div>
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                +
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                --
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               <span class="crayon-o">
                --
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               <span class="crayon-o">
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                --
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                +
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               <span class="crayon-h">
               </span>
              </div>
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               <span class="crayon-h">
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               <span class="crayon-o">
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               <span class="crayon-h">
               </span>
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                +
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               <span class="crayon-o">
                --
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                --
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                --
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                +
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               </span>
              </div>
              <div class="crayon-line crayon-striped-line" id="crayon-5768660113ff1937616296-8">
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                1
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               </span>
               <span class="crayon-e">
                row
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               <span class="crayon-e">
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               </span>
               <span class="crayon-h">
               </span>
               <span class="crayon-sy">
                (
               </span>
               <span class="crayon-cn">
                0.01
               </span>
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               </span>
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                sec
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                )
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              </div>
             </div>
            </td>
           </tr>
          </tbody>
         </table>
        </div>
       </div>
       <!-- [Format Time: 0.0025 seconds] -->
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